Amplitude of the Floquet wave spectrum of the reflected electric field for: (top) the PIBC solution in (5) and (bottom) the PIBC obtained by removing from the IIBC in (4) the contribution of the grounded slab evaluated at the incidence wavenumber. The amplitude of the FWs is shown for an TE-polarized incident wave at and a TM-polarized reflected wave at and , with a permittivity of the dielectric of .